This invention relates to rectifier assemblies for use in the rotors of high-speed, brushless, electric generators.
It is well known that the efficiency and reliability of electric generators, such as those used in aircraft power systems, can be improved by eliminating brushes, commutators or collector rings. Typical brushless generators included a pilot generator having a pilot armature winding mounted on the rotor of the machine. AC current induced in this winding is rectified by a rotating rectifier assembly and fed to an exciter field winding on the rotor. Rotation of the exciter field winding is used to induce multiple phase output power in a main winding located in the stator of the machine.
In order to reduce the size and weight of aircraft generators, it is desirable to increase the rotational speed of the rotor. At high operating speeds, prior art rectifier assemblies such as those which used type DO5 diodes located off center with respect to the rotational axis, have been subject to failure as a result of the high forces produced during such rotation.
Because of its position in the electrical circuit between the pilot generator and the rotating field winding, the rectifier assembly should be located within the generator shaft. It should also be at or near the shaft center to minimize rotational forces acting on its various parts. For high speed applications, the shaft should be as small as possible, thereby permitting a reduction of punching inside diameters and a reduction of stresses within the, punchings.
In prior art rectifier assemblies, lead wires from the windings penetrate the shaft to a screw terminal on the end of the rectifier assembly. At high speeds, the associated wires tend to fly outward from the shaft and must be restricted by various clamps and rings. It is therefore desirable to construct a rotating rectifier assembly which is not subject to the above problems associated with prior art rotating rectifier assemblies.